Furnace



Oct. 1, 1929;

W'. 'A. HARE FURNAGE Filed Feb.' 8, 1926 5 Sheets-Sheet Oct. 1929. w, A,HARE 1,729,776

FURNGE I Filed Feb. B, 192e s sheets-sheet 2 @Ww/whoa Ot.1,1929.wA-,HARE 1,729,7*16

4FURNAGE Filed Feb. 8, 1926 5 Sheets-SheetA 5 lf: l Q 91 s im g; l I I x@l O3 k) l u i Rv y N I C Q l q 7 i Q "u H 1f atroz neg V, Patented Oct.1, 1929 PATENT OF FICE `VTQIIiFBE'IID A. HABE, 0F DETROIT, MICHIGANFBNACE Application led February This invention relates to furnaces ofthe automatic stoker classvand more particularly to automatic stokersuse. An object of the invention is to provide a movable grate structurefor the automatic elimination of ash and clinker which structure isapplicable todomestic furnaces, particularly those of the round firevpot type. A furtherobject is to provide such a great structure which isapplicable to stokers of the under-feed type, and an arrangement wherebythe feeding of fuel and the operationof the grate structure is effectedin a simple and efficient manner. It is also an object to provide anautomatic Stoker of simple construction/which may be readilyapplied tocommon types of domestic furnaces, and embodying a construction whereinthe parts may be `readily assembled and as readily disassembled for thepurpose of replacement or repair. A further object is to provide in astoker for the purpose and of the present type, a simple constructionand arrangement for supplying air under pressure to the grate surfaceand retort for the purpose of maintaining combustion, and to providecertain other new and useful features in the construction andarrangement, whereby compactness and appli- @ability are secured andcost of manufacture is reduced.

Withthe above and other ends in view, the invention consists in thematters hereinafter set forth and more particularly pointed out in theappended claims, reference being had to the accompanying drawing inwhich- Figure 1 is a transverse vertical 'section through a structureillustrative of an embodiment of the present invention; l Fig. 2 is aside elevation of the structure shown in Fig. 1;

Fig. 3 is a plan view of the structure vshown in Fig. 1 with portionsbroken away and in section to more clearlydisclose the construction;Fig. 4

structure Fig. 3;

Fig. 5 is a perspective View of a pair of grate bars; and

is a transverse vertical section ofthe substantially' upon the line 4-4of designed for domestic- 8, 1926. Serial No. 86,786.

Fig. 6 is a transverse section of a plurality of bars in operativeposition.

lIn the drawings and as illustrated in Fig. 3, Aindlcates the base ofany old and well known construction of domestic furnace upon which upperstructure B forming the fire chamber of the furnace is supported intheusual manner. Within this base is supported a wind boxl of circularformation in plan View, 'having a neck portion 2 extending through adoor or\ other opening, in a side wall of the box A and through whichneck portiony air 1s supplied under pressure in any suitable manner, tothe box. Arranged axially with- 1n the box 1 is a vertically extendingfuel chamber 3 open at its upper end and supported by an axial gearchamber 4, the upper wall of which closes the lower end of the fuelchamber, and leading laterally from the fuel chamber 3 is a tubular fuelpassage which I extendsoutwardly within the neck portion 2 of the windbox to a point outside the fur- 'naple to receive fuel at its outer end,as from a opper or other holder, not shown, and within this tubularpassage is a screw conveyor 6 for conveying the fuel inwardly to thefuel chamber 3 and to a vertically arranged screw conveyor 7 within saidchamber. Secured directly upon the'upper end of the chamber 3 is aretort comprising a tubular upwardly and outwardly flaring magazine 8into the -lower end :of which fuel is forced by the screw 7 and a twyeror cap ring 9 which is supported upon the upper end of the magazine andforms' an upward extension of the l86 magazine and rounded upper end orthroat therefor, said magazine and twyer ring thus t together forming aretort or circular fire pot which is supported axially of and ext endsupwardly for a short distance within the lower end ofthe fire chamber ofthe furnace.

The twyer ring 9 is formed with an inwardly and downwardlyv extendingflange 9", the upperv surface of which forms a continuationof theoutwardly Haring curved inner surface of the magazine 8 and the undersurface' of `this flange is formed with ribs 9b to rest upon anoutwardly curved fiange 10 von the upper end of the magazine 8 and spacethe twyer ring from the flange 10, thus providing air entrance openings11 opening into the upper part of the retort with said ribs formingbetween them and between the twyer ring and flange 10, air passageswhich are in communication at their outer ends beyond the -outer edge ofthe flange, with the air box 1 to receive air under pressure therefrom.Certain of said ribs 9b are formed with downv wardly extending portions9c toengage the from the under side of the ring and spaced .the outerends of the air from the peripheryof the flange 10 to direct theupwardly flowing air under pressure into passages formed by the ribs 9b.vThis annular rib 9 also serves to divide the air stream and deflect apart thereof outwardly beneath the outer annular edge of the ring 9 andthrough a small space 12 between said edge and the inner ends of aseries of' radially extending grate bars 13 surrounding the twyer ringand extending outwardly therefrom, to supply a small l' amount of airunderpressure to the upper or inner edge of said grate along the entireouter edge of the ring and maintain combustion along said edge,

The several grate bars 13 are supported at i their inner ends upon theupper edge of a movable ring 14 for imparting thereto al movement'forworking the fuel flowing over the -twyer ring'from the retort or firepot, outwardly along said lbars and to cause,- the ash and clinker topass from the outer ends of these bars and fall into the ash pit formedby thebase A. To connect these several grate bars 13 to the ring 14 attheir inner ends `so I rthat they will becaused to move therewith,

each bar 13 is formed with a notch 15 at its innerend to receive theupper edge ofthev ring 14. All of the grate bars are" thus detachablyattached'to the movable or grate bar actuating ring 14 to movetherewith, said bars resting at their outer ends upon a rotatabldsupporting or ash ring 16 having a broad flat upper Surface upon whichthe bars may rest and slide freely when motion is imparted y thereto bythe ring 14. This ash ring- 16 is extended voutwardly beyond the upperflat surface upon which the bars rest and is preferably formed with aseries of annular `steps 17-extending outwardly and downwardly be- Ayond the upper bar supporting surface of the r1ng to receive the ash andclinker discharged from the ends ofy said bars, and this ash orl gratebar supporting ring is rotated upon a gear at diametrically oppositepoints. This ring gear member Vrests with its lower edge riding upon therollers with the ash ring may be freely rotate and to impart anintermittent rotative movement thereto, said ring gear is formed withratchet teeth 24 on the under side of an outwardly extending annularflange 25 on said ring gear, said ratchet being engaged by a pawl 26pivoted intermediate its ends upon one end of a lever 27 having apivoted support intermediate its ends upon a bracket 28 secured* theouter side of the windbox wall, the loweend of said lever 27 beingconnected by a link 29 to a crank disk 30 on the outer end of a driveshaft 31 which shaft extends through the wall of the wind boxand acrossthe same, and into the gear box 4. Rotation of sha-ft 31 therefore swins the lever 27 upon its sup'- port, through t 'e crank and linkconnection, and as the pawl 26 is carried by the upper end of thislever, it will' engage the ratchetteeth 24 during one movement of saidlever, and rotate the ring' gear in one direction, and

Avduring the other swinging movement of said thereof will hold itsopposite end in engagement with the ratchet teeth and to support thetail end of said pawl, a roller 32 is mounted upon the bracket 28'. Thetail end of the pawl rides freely upon the roller and the rollerprevents the pawl from exerting an upward thrust on the ratchet ring,which thrust might otherwise tend to lift the ring gear olf the suporting rollers 18, which rollers are provi ed with -flanges 18a toengage and center the ring gear concentric with the axis of the retort`8. x

As the ring gear 20 is in constant engagement with the piions 22, thesepinions are to impart extending studs or pins' (projecting radially fromthe i box 1, said ring 16 being rig- 18 so that it, together v .diateits ends, the weight Aof the tail end l of the several radial grate bars13 are con- 'l nected so that said said ring 14` is provided atdiametrically opposite sides, with outwardly extending arms 33 which areformed integral with or rigidly vattached at their inner ends to'saidring 14, and at their outer ends are provided,

eachy with an eye forming a bearing to receive a pin 34 on each pinionextending 'upwardly gratel bars will be moved,

from the side Athereof and positioned laterally of the axis of turningmovement of the said pinions to form crank pins for transmitting motionfrom said pinions to the ring 14. As said pinions 22 are positioned atdiametrically opposite sides of the ring member 14 and as the arms 33are rigidly connected to said ring, the motion of travel of the crankpins about the axes of the pinions, is directly imparted to the ring 14,thus imparting to all of the radial grate bars a motion defined by thetravel of the crank pins during each vrotation of the two pinions, theouter endsfof the bars sliding upon the upper flat surface of. 'the ashring 16, and moving at their .inner ends with the actuating ring 14,which ring' slides freely upon the flat upper surface of an annularflange on the upper end of the wall .of the wind box 1.

Power for rotating the grate supporting ring 16 through the medium ofthe pawl 26 and ratchet 24 and for imparting movement' to the severalgrate bars through the medium Y of the ring 14, is transmitted from anysuit- The several grate bars 13, as shown inA Fig.v

3, are tapered throughout their length and are of, greater width attheir outer than at their inner ends so that when. placed side by sidein'radially extending position about the retort, they will fit closelytogether and form,

ineflect, a continuous annular. grate ,spanning the space between theoperating ring 14, and the.ash ring .16, with the inner ends of the barslying beneath the outer edge of the twyer ring 9 but free to moverelative thereto, and substantially filling the space between the upperend of the grate bar operating ring 14 and said edge of said twyer ring,there being only sufficient space 12 between the upper face of the endsofthe bars and the edge of the twyer ring to permit a small `amount ofair under pressure to escape from the wind box and maintain combustionupon the upper ends of the grate bars, which space is always kept clearby themovement of the bars relative to this cap ring of thetwyer.

'krlo prevent too rapid a discharge of ash and clinker from the lower orouter ends of the. grate bars and from the ash ring 16, a filler ringmember 42 iinserted between the upper end of the base A and the lowerend of the structure B, said ring being formed with an inwardlyextending annular flange 43, of an innery diameter to provide a narrowspace between theouter ends-of the grate bars and said flange, with theflange projecting inwardly over the stepped portion `17 of the ash ring16. This filler ning also serves as an adapter to permit of theadapting. of

what inrdiameter and also to vary the height of the base, ring adaptersor filler rings of different sizes in diameter and cross-sectionl beingprovided to take care of such variations. j

As before stated, air under pressure issupplied to the wind box Land aportion of this air is admitted to the retort or fire pot through thepassages formed between the ribs 9* on the twyer ring 9 as described.Forced draft or a portion of this air under pressure also escapesthrough the annular space at the outer edge of the twyer ring tomaintain combustion on the upper ends ofthe grate bars, and` to provideforced draft for maintaining com-y bustion upon the surface of theannularv grate formed by the several grate bars 13, each bar is formedwith a recessed side to co-operate with a'like 'recessed side of anadjacent bar in forming a passage 44 open at the inner ends of the barsto receivey air under pressure from the wind box and this passage opensinto the base A to furnaces 'which may vary some- ..10 i

the inner lendI of a chamber 45 formedA by recessingadjacent sides ofadjacent bars so that one-half of each chamber will be in one bar andthe other half in the other bar. Vhen the bars' are placed side by sidein close contact, a closed chamber is formed extending throughout themain portion of the length of said bars and is open through the outerend or the end face which rests upon the ash ring 16 so that the outerends of said chambers will be closed by said ring. The edge of thebottom wall 46 ofthe recess in one bar fits closely againstthe likewall. of the recess inthe adjacent bar, tightly-closing' the lower sideof each chamber 45 but the upper walls of these recesses, the outersurface of which forms the uppei` grate surface, are formed to 'providenarrow longitudinal 4slots 47 openf ing through the` grate surface andproviding for the escape'of air from-the chambers 45',

upwardly through'the grate surface to maintain combustion thereonthroughout the.

length thereof.. A rib 48 on each bar co7 operates with a like rib on anadjacent bar to form a division baille betweenthe inner end of' eachchamber 45 and passage 44 leading thereto, this baille extendlngdownwardly from the upper wall of the chamber to near the bottom wall 46thereof, so that air under pressure will enter the upper or inner end ofeach chamber near the bottom thereof to blow any-ash which may fall intothe chamber through the slot' 47, along the bottom toward the lower orouter end ofthe chamber, which end is closed by the ash ring. The gratebars are all so shaped as to provide an outwardly and downwardlyinclined grate lsurface to assist in the discharge ofiash and-clinkerfrom their outer ends onto the ash 'ring and also to incline thechambers so that the ash entering through the air discharge slots in thegrate surface, will readily nd its way into the lower or outer end ofeach bar to be discharged therefrom when said lower open ends of thebars pass over an opening 49 (see Fig. 3) in the upper surface or wallof the ash ring upon which the outer ends of these bars rest and slide,the outer open end of each bar passing over said opening once duringeach complete rotation of the ash ring. 4 In order that the dischargeend of each bar may be gradually opened as said end asses` over theopening 49said opening is e ongated with its length extending diagonallyof the upper surface of the ash ring `and its circular path of travel.The air pressure chambers of the several bars are therefore swe t cleanonce during each rotationof the ash ring and during the remainder of`such rotation, are closed by said ring except that thc air underpressure contained in said chambers may at all times escape through thenarrow slots' 47 in the gra-te surface.

In order to supply air under natural draft to the grate surface, theside of each grate bar 13 opposite that which is recessed to form thechamber 45, is cut away throughout a major portion of its length toform, together with the adjacent bar which is cut away in a like manner,a slot 50, which slots open through both up er and lower surfaces of thegrate structure ormed by said bars and provide passages for the directupward flow of airl through the grate from the space below, or the ashpit, thus providing for the supplying of air to maintain combustion uponthe grate by natural draft so that the fire may be maintained, shouldthe means for supplying air under pressure to the wind box fail for anyreason, and itis obvious that natural 4draft alone may be relied upon.to maintain combustion upon the grate, by reason of the forming of thebars in this manner at both sides and providing natural draft slots atboth sides of each bar, eliminating the forced draft .air chambers. Itwill be noted that each. bar

adjacent its ends is of full width to contact adjacent bars and formtight joints therewith, providing in effect, continuous grate portionsat the inner and outer ends of the bars, said inner ends thus togetherforming a wall to close or. substantially close the space between theupper end edge of the operating ring 14 and the outer edge of the twyerring 9.

Preferably, the` retort member 8, adjacent its upper outwardly flaringend which is ,provided with the outwardly and'upwardly curved annularflange 10, is formed with an internal upwardly open annular groove 51adapted to receive and retain ash for the purpose of insulating thisportion of the magazine or fire pot against the extreme heat generatedat this point due -to the entrance through the openings 11 directlyabove, of airA under pressure into the fire pot. Overheating of theretort woulddistill out coal gases from the coal in the retort, whichgases would pass downward inthe retort throughthe coal in the chamber 3and finally find their way out through the fuel passage 5. `Thisoverheating is prevented by the insulation provided by between the baseand upper part or body off the furnace, further insures adaptability andprovides an inwardly extending fiange or ledge to surround the gratestructure with a restricted annular opening between this flange andoutervends of the grate bars so that theV discharge of ash and clinkerfrom the grate may be regulated, said opening being such that it will beclogged by accumulation of ash and clinker lon the ash ring provided theash ring is not moved, but a rotation of the ring will cause a dischargeof the ash from the ring and therefore by regulating the speed of thering, the discharge of ash and clinker may be accurately controlled tocontrol the fire on the The construction whereby the retort ring cap'9is detachably locked in place upon the retort and in turn detachablyholds the several grate bars assembled upon their actuating ring 14,provides for ready assembly and disassembly, and an efficient movementof the entire grate structure is secured by the application of motion tothe actuating ring 14 through the medium of two crank motions impartedin unison thereto by the pinions 22 and eccentric connection of the ringto these gears by the crank pins 34 on the gears and rigid arms 33 onthe ring at diametrically opposite sides of the ring. The movementimparted to the grate structure is therefore a movement corresponding tothe path of travel of the pins'about the two axes of the pinions andwithout ,rotation of the gratestructure upon its own axis. This motionas well-as the motion of the ash ring 13, is intermittent due to theturning of the ash ring by the pawl and ratchet which imparts a very orfire pot and' the 'ash and clinker is discharged from their outer endson to the ash ring which, by its rotative movement graduall dischargesit into the ash pit. This'longitu inal movement of the grate barsrelative to the retort cap ring-9 which is stationary, also keeps thenarrow air space between the upper ends of the bars and the outer edgepfsaid cap ring clear so that air under pressure may enter the fire allalong the edge of the cap and maintain combustion at the upper ends ofthe grates where the fuel forced upwardly in the retortoverlows the capring.

The construction and arrangement of elementsof the present inventionparticularly adapts the same to a circular construction and makes itparticularly adaptable to furnaces having circular fire chambers butobviously the construction and arrangement may be varied within thescope .of the appended claims, to adapt the invention to installationsother than that illustrated. Further, the construction is such as toprovide a very compact device which may be readily installed in afurnace baseof the usual dimensions with the neck portion 2 throughwhich fuel is fed and air under pressure is conducted, extending throughthe usual base opening or ash door,

"with said neck portion rigidly secured to the base by means of a flange52 on the neck bolted or otherwise secured to the base around theopening, so that the entire structure within the base is supported bythe neck portion, with the space all around the structure and beneaththe same within the base, free from obstructing supports and so that theash and clinker may be readily removed from the base or ash pit.

Havingfthus fully described my lnvention,

- 1. In la furnace, the combination of a plurality of radially extendinggrate bars together forming a grate, and means for moving said gratebodily in a horizontal plane l along a'closed path having a verticalaxis.

2.In a furnace, the combination of a plurality of radially extendinggrate bars. together forming a circular grate, and means for impartingto said grate a non-rotative bodily circular movement in a horizontalplane.

3. In a furnace,'the combination of a central fire pot, a plurality ofgrate bars together forming an annular grate surrounding said fire pot,and means for moving sald -bars central fire pot, a pluralit tendingradially from sai fire pot and forming a grate surrounding the ot andmovable relative thereto, means for eeding fuel into the lower end ofthe fire pot, and an ash ring at the outer ends of said grate bars.

6. In a furnace, the combination of. a central fire pot, a plurality ofgrate bars extending radially from said fire pot and forni'- ing'a gratesurrounding the pot and movable re tive thereto, a twyer ring on theupper end of the pot, means for moving the grate relative to the pot andmeans for introducing air under pressure into the fire pot through saidring. 7. In a furnace, the combination of a central fire pot, aplurality of grate bars extending radially from said fre'pot and forminga grate surrounding the pot and movable relative thereto, said barsbeing formed to provide air discharge openings through the upper surfaceof the grate, a twyer ring on the upper end of said pot with itsperiphery overhanging the inner ends of said bars, means for introducingair under pressure into the fire pot through said ring and into the fireon the grate surface through Said air discharge opening, .and means formoving the grate relative to said fire pot.

8. In a furnace, the combination of a central lire pot, a plurality ofgrate bars extending radially from said ir'e pot and forming a gratesurrounding the pot and movable relative thereto, a twyer ring lon theupper end of the pot withtits periphery overlying the -inner ends ofsaid bars, anash ring at the outer ends of said bars to receive ashtherefrom, me ans for moving said errate as a whole, relative to saidpot and to sald ash ring, and means for moving the ash ringy relativelyto the outer ends of said bars to effect the disof grate bars exchargeof ash from the outer ends of the bars. Y

9. In a furnace, the combination of a centralfire pot, a pluralityof'grate bars ex-4 tending radially from said fire potand forming agrate surrounding the pot and movable relative thereto, a twyer ring onthe upper end of the pot with its periphery overlying the inner ends ofsaid bars, an annular member supporting the inner ends of'said bars, anash ring supporting the outer ends of said bars, and means for movingsaid annular member to' move the bars lengthwise.

10.I A furnace as characterized in claim 9 including means for rotatingsaid ash ring about the axis of the-fire pot.

11. A furnace as characterized in cla'im 9 wherein said means formovingsaid annular member is actuated by @rotative movement of said ashring.

12.` An automatic .stoker for domestic furnaces having a base providedwith an opening in'one side thereof, said Stoker in-v cluding an upwardlextending fire pot, a

neck portion extending laterally 'of the fire Y pot and forming a fuelVpassage leading to the from the-upper end of the wer end of theextended throug A and secured to .the base adjacent the o n'- ing, meansin said neck portion for f in fuel into the lower end ofthe fire pot, ana grate structure to receive fuel overflowing fire pot,said stokate andfuel feeder including said'ire'pot,

in said base solely inglmeans being suppo by said neck portion.

13.. A device ef che character described *end as characterized in claim12, and whereinV said neck ortion provided with a passage for air un erlressure and a t er 1s mount- *ed upon the re pot and provided with airpassages opening into the fire pot and coinmunicating with said passagein said neck portion.

14. A device of the character described and Vzas-characterized in claim12, and wherein a driving shaft extends longitudinally of'said neckportion therein and 'means is provided structure `and move at the innerend of said shaft 'for transmit-` ting motion therefrom to operate thegrate A the same relative to the 15.'Avde v1ce of the characterdescribed i and as set forth in claim 12, and a filler ring forinterposition between the upper end of the .furnace base and upper partof the furnace.

`16. A deviceof the character described and as set forth in claim 12,and a `filler rin for interposition between the upper end o the ,furnacebase and upper part of the furnace,

Y Vsaid, ring bein provided with a Ilan e extending inwar y toward theend of sai grate structure to restrict the discharge of ash and clinkerfrom the grate.

17. An automatic stoker for domestic furnaces having a base providedwith an openl portion for feeding fuel into the fuel chamber, meansint-he fuel chamber for feeding fuel into the' lower end of the firepot, a frate structure extending radially from the Ere pot to receivefuel overflowing therefrom, said grate structure being mounted upon thestructure forming the fuel chamber and neck portion, and means formoving the grate. structure relative to the ir'e pot.

18. An automatic Stoker as'characterized in claim 17 and furthercharacterized in that .Said structure forming said fuel chamber is .alsoprovided with a -wind box and said neck portion of` the structure isformed with a t, said neck portion being the opening in the baseVv passae 'for air under pressure leading'to the i wind ith air passages openinginto the pot and communicating with the wind box.

' 19. An automatic stoker as characterized in claim 17 and furthercharacterized in that said neck portion is of a length .to position thex, and a twyer o n the fire pot formedV i fire pot centrally of saidbase and said grate v I structure com rises p uralify extending ra 'allyfroin sai fire pot with their inner ends supported adjacent the uppereid of the pot, and an ash ring forming a support for the outer. ends ofsaid bars and movable relative theretov and upon which the bars are freeto` move when the grate structurl is moved relative to the fire pot.

20. An automatic Stoker as characterized of grate bars in claim 17 andfurther characterized in that said neck portion is of a length toposition the fire pot'centrally of said base and said grate structurecomprises 'a plurality of grate bars extending radially from said firepot with their -inner ends supported adjacent thc 11D i ed upon thestructure forming the fuel cham- 'ber and support for the lire tionabout the fire pot axis.

21. An automatic Stoker as characterized pot, for rotain claim 17 andfurther characterized in that said neck portion is of a length toposition the fire pot centrally of said base and said "'ate structurecom rises a plurality of grate ars extending ra 'ally from said fire potwith their inner ends supported adjacent the upper end` of the pot, anannular ash ring having an outer ends o bein formed with outwardly anddownwarily stepped annular surfaces and mounted upon the structureforming the fuel chamber and support for the fire pot for rotation aboutthe fire pot axis, and an annular filler ring for interposition betweenthe furnace base and upper furnace structure, said ring bein war y overthe stepped portion of the ash ring and restricting t tween the outerends of the the yfurnace wall.

22. A furnace Stoker including a supp`orting struct-ure forming a windbox and a fuel chamber, a fire pot mountcdcupon said fuel upper flatsurface upon which the the grate bars rest, said ash ring grate bars andchamber, a twyer mounted upon said fire pot eannular opening be-v formedwith a flange extending inand formed with a'ir passagesopening intothe-fire pot, a member providing a wall forming an upward extension ofthe wind box and movable relative thereto, a series of grate barsengaging the upper edge of said Wall provided by said member and movabletherewith, a flange on said twyer overlyin the upper ends of the gratebars, saidwin -box claim 22 and including an ash receiving member uponwhich the outer ends of the grate bars are supported to move freelythereon and to span the space forming an upward extension of the windbox and said ash receiving member, and

means for moving said member forming the upward 'extension of the windbox wall, to

move the grate bars relative to said twyer. 24. A furnace stokerincluding a memberproviding a Wind box, a fuel chamber and a passageleading to the fuel chamber, an upwardly open and flared magazine. onsaid fuel chamber to receive fuel therefrom and forming a fgepot, atwyer ring on the upper end of' said magazine and formed with airpassages communicating with said wind box,

the magazine, with lugs to pass and a series of grate bars extendingradially from the magazine with the1r inner endsunderlying the outeredge of the twyer .witl a narrow 'space therebetween communicating withthe wind box, said grate bars together forming a grate surrounding the{ire p ot and chambers within the grate with openings from said chambersthrough the grate surface, said chambers being in communication with thewind box through the inner ends of said bars.

25. A furnace stoker as characterized in claim 24 and wherein said gratebars are tapered longitudinally in plan view, with their outer .ends ofgreatest width, whereby an annular grate is formed by placing said barsside by side and in contact throughout their length. A I- 26. A furnaceStoker as characterized in claim 24 and further characterizedin that theair chambersinsaid grate open through `an outer end portion of the bars,and in that a rotatable member is provided upon which the open outerendsof thebars rest to close said ends, said member being provided with anopening to register with the open ends of the barduring the rotation ofthe member relative to said bars.

27. A furnace stoker including a vertically arranged magazine with openupper and .lower ends andformed with 'an outwardly extending angeadjacent its upper end formed with notches, a twyer ring on saidmagazine formed with air passages opening into the upper end of saidmagazine and formed with downwardly extending portions to center saidtwyer upon said flange on said portions being provided throughthenotches in said flange and detachably hold said twyer in place.

28. A furnace Stoker as' characterized in between said member said twyerring is formed with an outwardly extending peripheralange to overlie theinner ends of grate bars, and a series of grate bars is supported sideby side and in contact and in radially extending position to form anannular grate surrounding said magazine with the inner ends of saidbarsxproj'ecting beneath the outwardly -extending flange of said twyerring. v

29. In a furnace Stoker, the combination' of a member forming av windbox open at the top, a fuel chamber open at the top and a fuel passageleading tothe chamber, a magazine mounted upon the fuel chamber toreceive fuel therefrom, means for conveying fuel through said passageinto said chamber,

an annular twyer on the upper end ofthe magazine formed with airpassages opening into the magazine, an Vannular member uponthe wind boxforming an upward extension of the wall thereof surrounding themagazine,

-a series of grate bars operatively and detachably connected to andresting upon the upper edge of said annular memberand togethersubstantially filling the space between said edge of said annular member`and the annular outer edge .of said twyer with said bars togetherforming' an annular'grate surrounding the maga e, an ash ring rotativelysupported upon sa d member forming said fuel passage, fuel chamber andwindbox, upon-which ash ring the outer ends of said grate bars rest, andmeans for moving the annular memberupon which the inner ends of thegrate bars rest, to move the grate relative to' the magazine and twyer.

" 30. A furnace Stoker as characterized in claim 27 and furthercharacterized'in that claim 29 and including a pawland ratchet forrotating said ash ring about the axis o f said magazine and said meansfor moving saidannular member upon which the innerends of the grate barsrest, includes cranks operatively connected to said annular member.`

31. In a furnace, the combination of a` lurality of grate bars forming agrate, an rotating means for imparting to said grate, a circular motionin a horizontal plane, said lmotion being .defined by the revolution ofsaid rotary mean ing axes.

32. In rality of gratebars forminga grate, means for imparting to saidgrate, a circular motion in a horizontall plane, said means including aplurality of cranks simultaneously rotatable about separate upwardlyextending axes and defining by their revolution about said axes saidcircular motion.

and

In testimony whereof I affix my signature.

- WILFRED A. HARE.

about upwardly extend- 1 a furnace, the combination of .a plu-

